Patent GB-744974-A (GB)
Abstract: 744,974. Calculating-machines. FELT & TARRANT MANUFACTURING CO. Jan. 30, 1952, No. 2491/52. Addition to 729,820. Class 106 (1). A calculating-machine with a multi-denominational accumulator having numeral wheel gears that are separable from their actuators by zeroizing means to allow associated springs to return the numeral wheels to their zero position, comprises additional means for preventing certain of the denominational orders from returning to their zero positions on zeroizing. The additional means comprises a detent device mounted in each of said orders, means for moving the detent devices into engagement with their associated gear trains on operation of the zeroizing means, and a control mechanism normally disposed in operative position to block such movement of the detent devices by said means but movable manually to an inoperative position to enable such geartrain-engaging movement of the detent devices in response to the operation of the zeroizing means. The various parts of the calculating- machine are housed in a casing 21 and supported therein by side-plates 22, with intermediate plates 23, Fig. 8, disposed between the various mechanisms of the several denominational orders of the machine. Nine digit keys 25, Fig. 1, are provided in each column of the machine at the forward end of which the accumulator mechanism is mounted. Accumulator mechanism. Each numeral wheel driving gear train in the accumulator mechanism includes a spring winding gear 32, Fig. 2, normally in mesh with a transmitting gear 31. Each drives a numeral wheel gear 36 through an intermediate gear 34. Each numeral wheel gear 36 is operable by its associated keys 25 acting through known means on the said gearing. A numeral wheel 38, Fig. 8, is secured to each numeral wheel gear 36. Known zeroizing means. The spring winding gears 32 are on a shaft 33 in a frame that is pivotally mounted on a transverse shaft 35, the spring winding gears 32 being thereby disengageable from the transmitting gears 31 to allow the numeral wheels 38 to be returned to zero by the spring-tensioned gears 32. Such detraining movement of the swinging frame is accomplished by forward movement of a zeroizing lever 71, Fig. 1, coupled by suitable linkages to the swinging frame, the frame remaining in its displaced position following the release of the zeroizing handle 71 until a digit key 25 is subsequently actuated. A rod 177, Figs. 2, 3 and 4, is swingably suspended by curved lever 178 from a shaft 37 on which the numeral wheels 38 are mounted. Fig. 2 shows the rod 177 in its normal position, but in response to the said forward zeroizing movement of the handle 71 the rod 177 is caused through a linkage arrangement to move to the position shown in Figs. 2 and 3. Preventing zeroizing of selected numeral wheels. The invention comprises means selectively operable to prevent clearing of some of the numeral wheels 38 upon operation of the zeroizing handle 71, so that any values contained in such numeral wheels will be retained therein while the other numeral wheels in the accumulator will be returned to zero position. This means includes a zeroizing control member 301, Figs. 1 and 8, normally held in its upper full line position of Fig. 1 by a spring 303, acting on a lever 80, to which the member 301 is pivoted. The control member 301 has a forwardly extending recessed lug 307, and is cut away on its rear edge to form a shelf 308. A crank arm 309, formed with a finger at its rear end that rests upon the shelf 308, is rigidly secured at its forward end to a flatted control shaft 311 journalled in the frame plates 22 and 23. The shaft 311 passes through the lug 307 of the control member 301. In the normal position of the control member 301 the flatted control shaft 311 is disposed in the lug 307, as shown in full lines in Fig. 1, the level of the shelf 308 then being such that the crank arm 309 is tilted upwards to cause the flatted surface of the shaft 311 to be inclined to the horizontal, see Figs. 1 and 3. When the control member 301 is depressed, the shaft 311 maintains the control member 301 in its depressed condition by engaging in a recess 314 in the lug 307. The depressed position of the control member 301, shown in dotted lines in Fig. 1, causes the level of the shelf 308 to be such that the crank arm 309 rotates sufficiently clockwise to cause the flatted surface of the shaft 311 to be horizontal, see Fig. 4. A number of detent levers 315, Figs. 3, 4 and 7, are mounted on a shaft 316 parallel with the flatted shaft 311, there being a detent lever 315 for each of the numeral wheel gears 36 that are lockable as a whole against rotation when the remainder of the machine is zeroized. With each detent lever 315 is a spring 321. Each detent lever 315 has a forward nose end 328 engageable when desired with the teeth of the corresponding numeral wheel gear 36, and a rearwardly extending finger 325 in contact with the flatted shaft 311. Operation. On operating the zeroizing lever 71, the transverse rod 177 moves as previously described from the dotted to the full line position shown in Fig. 3, thereby contacting an extension 323 of the spring 321 in a manner tending to urge the end 328 of each detent lever 315 into engagement with its corresponding numeral wheel gear 36. If the control member 301 is left in its inoperative position as shown in full lines in Fig. 1, however, the flatted shaft 311 engages the finger 325 of the detent lever 315, as shown in Fig. 3, and prevents the nose 328 of each detent lever 315 from engaging its numeral wheel gear 36. All the numeral wheels 38 are thus returned to zero when the zeroizing handle 71 is used to disengage the spring winding gears 32 from their transmitting gears 31. If the control member 301 is moved to its operative position as shown in broken lines in Fig. 1, the flatted shaft 311 is in the position shown in Fig. 4, so that when the zeroizing lever 71 is eventually operated to disengage the spring winding gears 32 from the transmitting gears 31, and to cause the transverse rod 177 to engage with the extensions 323 of the springs 321, in the manner urging the detent levers 315 into engagement with the numeral wheel gears 36, such movement of the detent levers 315 is no longer prevented by the flatted shaft 311. As a result, only those numeral wheels 38 that are not associated with detent levers 315, are now zeroized upon operation of the zeroizing lever 71. Specifications 556,239 and 640,347 are referred to.